A solid-phase radioimmunoassay for plasma progesterone

Abstract

A detailed procedure is presented for the assay of plasma progesterone. The routine assay is based on the use of antiserum which is covalently linked to microcrystalline cellulose, the double-antibody method being used as a reference separation system. This procedure gives high precision accompanied by small and acceptable losses of antiserum titre but without loss of sensitivity when compared with the double-antibody method. Ethanol is first added to the plasma (10vol. of plasma+1vol. of ethanol) after which a single extraction with light petroleum yields a constant recovery [92.4+/-1.2 (s.d.)% of added [(3)H]progesterone] and obviates the need for tracer recoveries on each sample being assayed. Distortions of the response curve owing to solvent residues have been almost eliminated. The assay can measure progesterone at all stages of the menstrual cycle when volumes of 200mul of plasma are used and this permits the detection of the periovulatory rise at its inception. Detailed specificity studies are presented for the assay end point itself and these are related to the responses to be expected in extracts of plasma. Progesterone-like activity was found in urine and a fourfold increase in excretion rates was observed between the follicular and luteal phase of the normal menstrual cycle.

Effect of actinomycin D on uterine prostaglandin production and oestrous cycle length in guinea-pigs

“…Progesterone was measured by radioimmunoassay using an antibody raised and tested by Dighe & Hunter (1974) and assessed for its suitability for use in the laboratory by Poyser & Horton (1975). The antibody had adequate sensitivity (limit 20 pg) and specificity (see Table 1 in Poyser & Horton, 1975) and the results obtained in the present study were in the expected range.…”

Plasma FSH, LH, the positive feedback of oestrogen, ovulation and luteal function in the ewe given bromocriptine to suppress prolactin during seasonal anoestrus

“…Progesterone concentrations were measured in a single-antibody solid-phase assay, similar to that described by Dighe & Hunter (1974), using a specific sheep antiprogesterone serum (Baird, Burger, Heavon-Jones & Scaramuzzi, 1974). All standards were diluted with buffer containing charcoal-treated calf plasma before extraction, so that standards and unknowns contained the same amount of plasma.…”

Regulation of oestrogen-induced LH release in male and female marmoset monkeys (Callithrix jacchus)

“…la-hemisuccinate-bovine serum albumin (BSA) conjugate. The specificity has been described by Dighe & Hunter (1974). Antibody to testosterone was raised in a goat immunized with testosterone-3-carboxymethyl oxime conjugated to BSA.…”